Thanks for your response.

resumé resume
Yes I've wrestled with that. At the moment there are both. Which is correct? What could you expect to be typed in? When it's ready I'll ask the site maintainers what they want! Thanks for the pointer.

Subs
The subs shown were for the benefit of the post. There are 752 stop words (I intend to increase this) and 182 html punctuation entities which are read in from separate files. I take your point though.

Double single quotes
Good point, thanks. I'd actually gone through the html, found the double single quotes (there were many) and removed them. There were also ` (back tick) quotes. Single and double :-)

words_all hash ref
I made a mistake there preparing it for the post. In the app I use a hash (%seen) to keep track of words found in each file and then:

push @{$words_all->{$_}}, $file_key unless exists $seen{$};
[download]

I think your method is better. Later, the count could contribute to some form of weighting system.

Again, many thanks, John